Concentration of minerals



y 24, 1934- G. A. CHAPMAN ET AL 1,968,008

CONCENTRAT ION OF MINERALS Filed March 26, 1929 k a O 9 0 O 0 O O 0 0 OO O 0 O '4 @fly' l 6 7 1K 1K 10 O 1/\1/\1/\1/\1 \1/\1/ .9 nvvervrorzs,

ATTORNEYS.

Patented July 24, 1934 UNITED STATES PATEN'F OFFICE CONCENTRATION OFMINERALS Application March 26, 1929, Serial No. 349,923

22 Claim.

This invention relates to the concentration of minerals, and is hereinillustrated as applied to the concentration of the phosphatecommercially known as bone phosphate of lime from naturally occurringphosphate-bearing material.

According to the present invention the concentration is efiected byprocedures which may include, skin or film flotation in which phosphateparticles ride upon the surface of water while silica and otherimpurities are wetted by the water and tend to sink; and which mayinclude differential separation under wet stratifying conditions, andwhich may include both skin flotation and wet stratifyingclassification. The process may be carried on or aided by tableconcentration wherein the silica, which tends to sink in the waterflowing over the table, is carried oil in the general directionof theriflies, while the phosphate particles, carried in or on the waterflowing across the riflies of the table, are delivered to a concentratelaunder, and are thereafter dewatered. The phosphate-bearing material isherein described as made easily amenable to such skin flotation orwater-flowing separation or both 5 by prior'treatment, as with analkaline substance, or with soap and oil, or .with alkali and a saponiflable oil. Variations of treatment may produce skin flotation, waterflowing separation with differential separation under wet stratifyingconditions, or both. Where an oil is used the oil selectively coatsphosphate particles, making them more amenable to separation.

In the form 01 the invention herein illustrated, film or skin flotationand other procedures are carried out together on a shaking table of ageneral type used in eflecting the concentration of metalliferousminerals.

Many forms of apparatus may be used in carrying out the procedures ofthe present inven- 40 tion, but the tests described in detail below werecarried out on a Wilfley table provided with a special deck as shown inthe accompanying drawing:

In the drawing Figure 1 is a plan view of the deck.

Figure 2 is an end view, and Figure 3 is a longitudinal vertical sectionthereof taken on a plane indicated by the line :n-a: in

Figure 1.

The deck 1, is shown as mounted on a stander deck frame 2, which in turnis mounted in the usual manner for longitudinal vibration by the usualdevices so that the whole vibrates as a unit.

The deck 1 is provided with riffles 3, extending longitudinally of thedeck. A thick pulp of phosphate-bearing material was fed, through ahopper 4 at the upper end 5 of the upper side, to the deck, and thevibrations of the table tended to carry the silica and other impuritieslength wise of the table and in the general direction of m the rifliesand to the lower end 1 of the table, discharging it, through V-shapedcuts 8 at the lower end 7 and between the riflies 3, into an end ortailings launder 9. The pulp particles were continually washed bystreams of water flowing o5 transversely across the riflies from a feedpipe 10 along the upper side 6, which carried and discharged phosphateparticles into a concentrate launder 11 at the lower side 12 of thedeck. The V-shaped cuts prevented gangue from building up along thelower end 7 of the deck. The surface of the deck was not quite flat,sloping about an eighth of an inch from each side toward the center sothat a long pool of water tended to form between .the central rlflles. 7

Many phosphate particles float on the water surface as a skin or fllmfloat and are carried oil into the concentrates launder 11 by thetransversely flowing stream of water. Other phosphate particles, many ofthem in flocks associated with air bubbles, form aggregates or looselybonded agglomerates and, in suspension in the water, or resting lightlyon the silica or other impurities are carried transversely, separatingthemselves from the endwise movement of the other particles by the usualaction of a table.

The following tests were carried out with the apparatus just described.The material used was the phosphate-bearing tails resutling from theconcentration by screening of the product of the No. 11 Mine of theInternational Agricultural Corporation at Mulberry, Florida. Thematerial was mostly finer than 14-mesh, and had been largely deslimed.The principal ingredient of the gangue was silica, but it also containedthe objectionable ingredients iron and alumina.

In one test phosphate-bearing material was made into a thick pulp andtreated with caustic soda in solution equivalent to 0.4 pounds per tonof solids, then mixed with 1.2 pounds red oil (oleic acid) and fourpounds of fuel oil, both per ton of solids. This formed soap and leftthe fuel oil as an oily material which coated the phosphate particles.The thick pulp was then agitated as for flotation, fed to the table withmore water and concentrated thereon by the vibrating action of the tableand transversely flowing water as described above. The results are shownin the following table in which B, P. L. means so-called bone phosphateof line,

moisture was mixed quietly, with the minimum of agitation, with the sameproportions of the same agents and then separated by the samewater-flowing and vibrating table procedure into concentrate, middlingand tailing, the middling consisting of a concentratable mixture ofphosphate and other material. The results are shown in the followingtable:

A repetition of the last test, without attempting to separate themiddling product, yielded the results shown in the following table:

B. r. L. Wt. B. r. L. movw% Heads 100 21. 31 100 (Jones 29. a 1o. 4 91.s ails 70.4 .90 2.2

improves the richness of the concentrate and the recovery, and reducesthe amount of other agents required. So far as tested soap, especiallysodium oleate, and unsaponifiable oil, such as the fuel oil used above,were the best agents for effecting concentration. The best method ofadding the soap was to make it in situ from caustic soda and oleic acid,but other alkaline substances and other saponifiable oils proved useful,though less effective.

This process has also been found to be usefully applicable to theconcentration of the following minerals: Cassiterite, copper carbonate,beauxite, manganese oxide, iron oxide, barytes, lead carbonate, zinccarbonate and zinc silicate.

Having thus described certain embodiments of the invention what isclaimed is:

1. The process of concentrating phosphate ore which comprises adjustingthe water content of the finely-divided ore to insure having all theparticles thoroughly wetted and adding a selective flocculating agent tothe ore, mixing said agent with the ore'until loosely bondedagglomerates of phosphate mineral particles are formed which areadapted, when a mixture of said agglomerates and the gangue particlescontained in the ore is agitated under wet stratifying conditions, tosettle at a less rate than the gangue, then subjecting the mixture toagitative wet stratifying classification according to the relativesettling values of said agglomerates and the gangue andgathering thephosphate mineral in an overlying stratum.

2. The process of concentrating phosphate ore noeaoos which comprisesadjusting the water content of the finely-divided ore to insure havingall the particles thoroughly wetted and adding a selec= tiveflocculating agent to the ore, mixing said agent with the ore to form athin film or coating of said agent on each phosphate mineral particleand to at least in part form loosely bonded agglomerates of saidparticles, then subjecting the mixture to agitative wet stratifyingclassification according to the relative settling values of the treatedmineral and the gangue and gathering the phosphate in an overlyingstratum.

3. The process of concentrating phosphate ore comprising adjusting thewater content of ore of a degree of fineness such that the desiredmineral particles are substantially free from attached gangue particles,to insure having all the ore particle's thoroughly wetted, addingselective agents to the thus wetted ore and mixing said agents with theore to form loosely bonded agglomerated bodies of phosphate mineralparticles which are adapted when agitated under wet stratifyingconditions to settle more slowly than the said gangue particles, thensubjecting the resulting mixture to agitative wet stratifyingclassfication according to the relative settling values of said bodiesand said gangue and gathering the phosphate mineral in an overlyingstratum.

4. The process of concentrating a finely divided phosphate-bearingmaterial which consists in agitating the material with a fraction of onepercent of sodium soap and a fraction of one percent of petroleum oil inthe presence of enough water to wet the particles and adding water toform a freely flowing pulp and subjecting this pulp t0 agitative wetstratifying classification according to the relative settling values ofthe phosphate material and the gangue and recovering phosphateconcentrate in an overlying stratum.

5. The process of concentrating a finely divided phosphate-bearingmaterial which consists in agitating the material with a fraction of onepercent of sodium soap and a fraction of one percent of petroleum oil inthe presence of enough water to wet the particles and adding water toform a freely flowing pulp and subjecting this pulp to tableconcentration so that phosphate concentrate is discharged transverselyof the vibration of the table and tailings are discharged in the generaldirection of the vibration of the table.

6. The method of separating phosphate from fine phosphate-bearingsilica-containing material which consists in admixing a small proportionof soap and unsaponifiable oil with the material so as to selectivelycoat the phosphate particles with oil and flowing a stream of watercarrying the treated material across an obstruction so as to tend toretain the silica while the water carries onward the phosphateparticles, and collecting the phosphate particles.

7. The process of concentrating a finely divided phosphate-bearingmaterial which consists in agitating the material with a fraction ofphosphate material and the gangue and recovering phosphate concentratein an overlying stratum.

8. The process of concentrating a finely divided phosphate-bearingmaterial which consists in agitating the material with a fraction of oneper cent of soap and a fraction of one per cent of petroleum oil in thepresence of enough water to wet the particles and adding water to form afreely flowing pulp and subjecting this pulp to table concentration sothat phosphate concentrate is discharged transversely ot the vibrationof the table and tailings are in the general direction of the vibrationof table.

9. The process of concentrating mixed minerals wherein the values to beconcentrated contain a metal and oxygen in combination which comprisesadjusting the water content of such finely divided minerals to insurethe particles thoroughly wetted and adding a selective flocculatingagent, mixing said agent with the minerals until loosely bondedagglomerates of particles to be concentrated are formed which areadapted, when a mixture of said agglomerates and the other particles isagitated under wet stratifying conditions, to settle at a less rate thanthe other particles, then subjecting the mixture to agitative wetstratifying classification according to the relative settling values ofthe agglomerates and the other particles and gathering the agglomeratedparticles in an overlying stratum.

10. The process of concentrating flnely divided ores of non-sulphideminerals which comprises adjusting the water content of such an ore toinsure having all the particles thoroughly wetted and adding a selectiveflocculating a ent, mixing said agent with the ore to form a thin him orcoating on particles to be concentrated and to at least in part formloosely bonded agglomer ates of said particles, then subjecting themixture to agitative wet stratifying classification according to therelative settling values of the coated mineral and the other particlesand gathering the coated mineral in an overlying stratum.

11. The process of concentrating mixed minerals wherein the values to beconcentrated con-.

to agitative wet stratifying conditions according to the relativesettling values of the material to be concentrated and the otherparticles and gathering the material to be concentrated in an overlyingstratum.

12. The process of concentrating finely divided mixed minerals whereinthe values to be concentrated contain a metal and oxygen in combination,which consists in admixing a small proportion of soap and unsaponiflableoil with such minerals so as to selectively coat particles to beconcentrated with oil and flowing a stream of water carrying the treatedmaterial across an obstruction so as to tend to retain the otherparticles while the water carries onward the particles to beconcentrated, and collecting the parti--' cles to be concentrated.

13. The process of concentrating finely divided ores of non-sulphideminerals which consists in admixing a small proportion of a soap-formingradical and an alkali and an ble'oil withsuchanoresoastoselectivelycoatparticiestobeconcentmtedwithoil,andiiowingastream of water carrying the treated material acres an olstructionsoastotend to'retain the other particles while the water, carries onwardthe particles to be concentrated, and collecting the .particlesto beconcentrated.

14. The process of concentrating phosphateoreswhichconsistsinadmixingasmall portion of a soap-forming radical andalkali and animsae oilwlthsuclianoresoasto selectively coat phosphateparticles with oil forming agglomerates, and flowing a stream of watercarrying thetreatedmaterialacrossastratiiylng supportsoastotendtoretaingangueparticles while the water carries phosphateparticles onward, and collecting phosphate particles.

15. The proces of concentrating finely divided ores of non-sulphideminerals, which consists in agitating the particles of such an gore witha fraction of one per cent. of 'soap and a fraction of one per cent. ofpetroleum oil in the presence ofenough watertowettheparticlesandaddingwater to form a freely flowing pulp and subjecting this pulp toagitative wet stratifying classiflcation according to the relativesettling values of the material to be concentrated and the otherparticles,andrecoveringthematerial tobeconcentrated in an overlyingstratum.

18. The process of concentrating finely divided oresofnon-sulphidemineralswhichconsists in agitatingsuch anorewithafraction of onepercent. of soap and a fraction of one per cent. of petrolemn oil in thepresence of enough water to wet the particles, forming agglomerates andadding water to form a freely flowing pulp and subjecting this pulp totable concentration so that thematerialtobeconcentratedisdischargedtransversely of the vibration of the table andthetailingsaredischargedinthegeneraldirection of the vibration of thetable.

17. The process of concentrating phosphate ores comprising adjusting thewatercontent of suchafinelydividedoretoinsurehaving allthe particlesthoroughly wetted and adding a selective ilocculating'agent to the ore,admixing said agent with the ore to form agglomerates of phosphateparticles and subjecting the mixture to stratifying classification tosepmte the agglomerates from gangue particles according to theirrelative settling values, and gathering the phosphate a lomerates.

18. The process of concentrating finely divided ores of non-sulphideminerals comprising adjustingthe water content of such an ore to insurehaving all the particles thoroughly wetted and adding a selectiveflocculating agent and mixing said agent with the ore to formagglomerates of valuable mineral particles, and subjecting the mixtureto stratifying classification to separate valuable agglomerates fromgangue particles according to their relative settling values, andgathering the valuable agglomerates.

19. The process of concentrating minerals comprising adjusting the watercontent of an ore (of a sumcient degree of fineness to liberate thevaluable mineral from the gangue) to thoroughly wet the particlesthereof, adding a selective ilocculating agent to and it with saidparticles to form agglomerates of the valuable mineral content,subjecting the mixture to stratitying classification to separate theagglomerates from the gangue' according to their respective settlingvalues and collecting the agglomerates.

20. The process of concentrating phosphatebearing materials comprisingadjusting the water content of an ore (of a sufiicient degree offineness to liberate the phosphate from the same) to thoroughly wet theparticles thereof, adding a selective fiocculating agent to and mixingit with said particles to form agglomerates of the phosphate, subjectingthe mixture to stratifying classification to separate the agglomeratesfrom the gangue according to their respective settling values andcollecting the agglomerates.

21. The process of concentrating phosphate ores which consists inadjusting the water content of the finely divided ore to insure havingall the particles thoroughly 'wetted and adding a selective fiocculatingagent to the ore, mixing said agent with the ore to form a thin film orcoating of said agent on phosphate particles and to at least form inpart loosely bonded agglomerates of said particles, then subjecting themixture to agitative wet stratifying classification, and collecting aportion of the phosphate as a float on the water and a portion of thephosphate in an overlying stratum in the water.

22. The process of concentrating ores of nonsulphide minerals whichconsists in adjusting the water content of such a finely divided ore toinsure having all the particles thoroughly wetted and adding a selectivefiocculating agent, mixing said agent with the minerals to form a thinfilm or coating of said agent on particles to be concentrated and to atleast in part form loosely bonded agglomerates of said particles, thensubjecting the mixture to agitative wet stratifying classification, andcollecting a portion of the coated mineral as a float on the water and aportion of the coated mineral in an overlying stratum inthe water.

GEORGE ALBERT CHAPMAN. JOHN W. LITTLEFORD.

